DERIVATIVES - Effect of Customer Derivatives and Economic Hedges on Net Income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income		$ 10	$ 6
Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income		(6)	52
Customer derivative contracts | Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[1]	(3)	97
Customer derivative contracts | Other Income | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[1]	18	51
Customer derivative contracts | Mortgage Banking Fees | Residential loan commitments
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[2]	5	4
Economic hedges | Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[1]	15	(91)
Economic hedges | Foreign Exchange and Trade Finance Fees | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[1]	(14)	(50)
Economic hedges | Mortgage Banking Fees | Forward sale contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[2]	$ (11)	$ (5)

[1] Reported in foreign exchange and interest rate products on the Consolidated Statements of Operations.

[2] Reported in mortgage banking fees on the Consolidated Statements of Operations.